Separator



P 1949- s. G:SON SYLVAN 2,482,642

' SEPARATOR Filed Aug. 12, 1946 3 Sheets-Sheet 1 INVEN TOR.

I 527' 6:500 5 Ivan F107 3 f BY 1/ M M ATTORNEY p 1949. s. G:SON SYLVANSEPARA'I'OR Filed Aug. 12, 1946 3 Sheets-Sheet 2 INVENTOR. 5h 6:500 .5Ivan BY 7 A TTO/ZNEY Sept. 20, 1949. 5 G;$QN s v' 7 2,482,642

. SEPARATOR Filed Aug. 12, 1946 s Shee ts-Sheet 5 nvmvrozz.

577g 6:500 Sylvan BY mm m ATTORNEY Patented Sept. 2Q, 1949 PATENT OFFICE.SEPARATQR 'Stig .Ga o v 9kho1 weden s n "to American AirFilter Company,Inc., Louisville, Kyr, a' corp'orationofDelaware Application August 12,1946, Serial No. 689,885

It. has been proposedin such U. S. Patents as Knickerbocker No, 382,614,f'l3dehniiig No. 408,- 285, Goodier Nor'645;49; ana Haber 12934,- 467 toclean an air streamby passing it through a louver which effects asharpdeflection of the airflow, the dust particles being retainedfon theupstream side of ltlie louver and tending 'tOfCOI'ltinue intheiroriginal'direetion along that side. The upstream or deflecting"edges. of the slotdefining louver vanes".usually. extend at right anglestransverselyacrossi the air stream while the vanes and the approachingair extend at adjacent acuteangles tofopposite sides of the upstreamface of theflouver; Thisprinciple of cleaning has been ,applied 1 to"rotary structures in such U. 'S. patents as Linderoth No. 2,328,220 andpossibly Newcombe"No1;420;665. 'In rotary structures. the smallerparticles (usually one to 3Clai ns. 01.13347) twenty micronsmoreor'less); which are retained on the upstream "sidegof the louver,collect in an area adjacent tob'ut slightly spaced from the upstreamface of the louver. "They form a cloud which rotates about the louverand which, unless removed, increases in densitytoa critical value atwhich it loses'dust through the louver at apparently the samef rate itreceives "dust from the incoming air..

While the formation of; this cloud; is difiicult toexplain, it isplausiblethat the particles in the incoming air'ar'e made to spin orrotate at increasingl faster rates as they progressively approach thelouverand are thus subjected to aerodynamic forces'which-tend'to forcethe particles away from the louver, these forces being ucounter-balanced in thecloud area by the force of the air stream whic'htends to carry the particles through the louver.-'Ihe possibility thatthe particles are thus made to rotate' is indicated by these facts:first, the incoming air has one velocity component which is parallel tothe upstream face of the louver and which, during deflection, initiallydecreases in one direction between the beginning and reversal p0ints 'ofthe deflection from a. high maximumgvalue to zero and thenincreasesin'the opposite direction between the reversal and'end pointsof the deflection from zero to a high maximum value; and second, asaresultof this changing velocity component, the opposite sides ofeachparticle appear to be subjected" simultaneously to' relatively highand low air velocity corripoiients which apparently; bring about theaerodynamic forces that cause the particles to move away from thelouver; 1

' The problem .ofremovingflthe cloudforming dustfparticle's, withsufiicient rapidity to prevent the clouds from reaching the criticaldensity, is difiicult 'of' solution): If] Newcombes structure producessuch a, cloud, f he makes noattempt to remove it. Linderoth proposesasuction skimmer which is tangentially arranged relatively to the louversurface but this arrangement, if otherwise practical, is objectionablebecause it involves an independently operated suction" system.

' The principal object of invention is to provide a novel, simp le andhighly efie'ctive means forefficiently removing thecloud particles withsufiicient rapiditym'toprevent the. formation of a riti y d e lou -11;}.i

j nnother important object is to' provide a means which requires"little.orinoflauxiliary air flow in eflecting the removal'ar'id' whichavoids the necessityf of an independently operated dust removal air'systemg l, p 1' A further object is oprovide a novel form of louver. 1 j

heinvention isillustratedinthe accompany- 'ingdrawings wherei v j @Fig'.1 is an axia W ctionf partly inelevation, of one of myv rotary louver 1separators Fig. 2 is a section taken on line 2-2 of Fig. 1;

Fig, 3 is a perspectiveiviewiof a novel form of louver constructedinaccordance with my inv ti i I I] f Fig. 4 is a vector dia'gram'showingthe relative ngle; between "the approaching air and the louver;

K Fig. 5 is a cross sectional detail showing the relationship of thedust removing louver in a separatorof the general type described herein;"Fig. 6 is a similarf'view of the relationship used-in the-separator ofFig. 1; v I, y, -**I?igk 7 is -an 'a "a1 section-,"partly in elevation.showing one of my ,"rotary1ouver, separators with :o'ne form of 'secon'dary" dust removing system; Fig. '8 is an axial section of aseparator of the character shown in Figs l and 2 with a modified formofairinletf I Fig; 9 is amendelevation 'of-the Fig. 8 separapor; v :r og "Fig. 10' isanfaxial section of anotherembodimerit 'in which in'ylouver is stationarily mounted 'in-a cycIOne typeofhousihgjf; i

Fig! 11 is atop plan View of the separator of F a Y 1 12 showsanem'bodime'ntlike that of FigilO but with a'rota'r'y louveri and "Fig:13 is-a diagrammatic-section of a modified louver separatori'j H U r In*gener'al ternisf ai louvr separator constructed in accordance with myinvention for cleaning a primary flow of air may be described ascomprising: a dust separator louver having a series of slot-definingspaced vanes extending around an axis of rotation and across the path ofthe primary air flow, the louver vane being of a type which is adapted,upon the establishment of rotation relatively between said main air flowand the louver, to retain the dust on th upstream side of the louver;means for establishing relative rotation between the primary air andlouver; means constraining the primary air to approach the upstream sideof the louver in a manner such as to exert a force on retained dustparticles causing those particles to move to one side of the air flow;and means on the same side of the primary flow to remove said particlesrom said flow.

The separator shown in Figs. 1-3 includes a blower impeller I having anaxial inlet 2 mounted within a conventional blower housing 3 and arranged to be driven through a shaft 4 by some suitable source of powernot shown. The inlet face of the blower housing has an axial openinglarge enough to permit the impeller to be inserted into or removed fromthe housing. This opening is reduced to air inlet proportions, by acentrally perforated disc plate 5. A louver separator L is mounted inimpeller inlet 2 and arranged to project upstream therefrom, through thopening in disc plate 5. t

Louver separator L preferably is of the semispherical or dome shapeshown in the drawings It has: an annular base portion 6 forming itsdownstream opening and providing a means of securing it to axial inlet 2of the impeller I; an apex portion 1 at its opposite end; and a curvedside wall portion extending from the base end to the apex end andcontaining a series of louverforming slot-defining spaced vanes 8'.Vanes 8 may be cut or stamped from an integral sheet forming the curvedside walls or louver portions of the separator or they may be formedindividually and then secured to the apex and base portions of thelouver separator. While the vanes,

as shown, are longitudinally curved from the base end inwardly towardthe apex end, they may be made longitudinally straight and arranged toextend from the base end portion either parallel with the axis ofrotation or at an inwardly inclined angle to the axis of rotation sothat they form in one case a cylinder and in the other case a cone. I

To obtain good air cleaning results, I have found that it is necessary;first, to establish relative rotation between the incoming air and thelouver separator; second, to constrain the incoming air to approach theupstream face of the louver in such a manner as to provide an airvelocity component directed along the face of the louver axially towardone end or the other of the louver and thus toward one side or the otherof the primary air flow; third, toobtainasharp deflection of the air;and fourth, to obtain a somewhat uniform blower effect in the louver.

Relative rotation between the air and the louver may be obtained byrotating the louver or by rotating the air about the louver or by acombination of both. In Figs. 1-4 such rotation is obtained solely byrotating louver separator L.

In Figures 1-2, the incoming air is constrained to flow axially towardlouver separator L' by an inlet piece 9. The shape of this piece isco-ordinated to the shape of the upstream face of the louver separatorto accommodate the inlet flow of the air in a well known manner such asto provide a uniform flow of air toward, or a uniform distribution ofair over, the upstream face of the louver separator. Preferably alsovanes 8 of the louver are spaced so that the total free area of thelouver slots is approximately 10 greater than the cross-sectional areaof the inlet piece 9 at its upstream end. With this arrangement, as theair axially approaches louver separator L, and while it turns to passinwardly through the slots between vanes 8, it has a velocity componentwhich extends along the upstream face of the louver and in the directionof the base of the louver. This axial velocity component exerts on thecloud forming dust particles, which are retained on the upstream side ofthe louver, a force causing those particles to move, as a whole, axiallythrough the cloud forming area toward the base of the louver separator.In other words, this axial velocity component of the incoming air isutilized to move the cloud forming particles to one side of the primaryair flow, such side corresponding, in the structures of Figs. 12, to thebase end of the louver separator.

To secure sharp deflection of the air by the louver, the incoming airmust have a small or acute angle of relative approach on one side of theupstream face of the louver, louver vanes 8 should form an adjacentacute angle on the opposite side of the same upstream face, and theseangles must point in a direction opposite the di rection of louverrotation. With a rotating louver, the relative approach angle is, ofcourse, determined, at any one point, by the tip speed of the rotatinglouver at that point and that velocity component of the incoming airwhich is directed radially'inward. For example, in Fig. 4, a vane 8 isshown'rotating counterclockwise about center C with a tip speed TS, thecorresponding relative velocity of the air being shown by the oppositeair speed vector AS. With the inward air speed shown by the vector IS,the resultant air velocity will correspond to the vector RAV, this beingthe relative velocity of the approach air while the angle X representsthe angle of approach.

With relative rotation between the louver and the incoming air, it willthus be seen that the relative approach angle is determined by thatvelocity component of the air which corresponds to the tip speed of thelouver and the radially inward velocity component of the air. This angleshould be about10 to 15 although it may vary over a somewhat widerrange. The average inclination angle of the vanes will normally reachbetween 10 and 30, it being understood that the inclination of theupstream portion of the width of the vanes will normally be difierentfrom the downstream portion of the width and also that the inclinationwillvary with the radius of rotation to compensate for the lower tipspeed.

To secure a somewhat uniform blower efiect, the angle of relativeapproach of the incoming air and the width, cross-sectional shape,and'inclination of the vanes must all be co-ordinated in a manner suchthat the air at the base end portion of the vanes discharges at onevelocity and in one direction to produce a certain static pressure witha certain total pressure while the air, at other vane portions ofprogressively smaller radii, must discharge'at progressively highervelocities in appropriate directions to produce progressively lowerstatic pressures with the .same total pressure. This, apparently, hasnot heretofore been appreciated in the air cleaning art but once thenecessity of co-ordina-ting such factors, to produce a more or lessuniform blower efi'ect, is realized, then it becomes obvious that themode of effecting such co-ordination" is a matter of routine blowerdesign; hence it should sufiice to say that, in the present case, thevanes, in accordance with well known design principles, are made .todecrease, from the large base end .to the small apex end, in width,camber and inclination; If the vanes were individually formed ofconstant or even increasing width: from the large base end tothe smallapex end, the camber and inclinationshould bechanged accordinglytoprovide a uniform blower effect with the same approach angle.

Whenan air flow is set up through the rotating louver above described,dust particles will. be retained on the upstream side of the louver andthese particles will form a cloud. Since the in coming air, passingaxially through inlet piece 9, approaches the louver axially and thenturns inwardly to :pass' through the louver, it will be appreciated thatan axial component of this flow is directed toward the base end of thelouver. This axial component acts on the cloud, forcing its particlesaxially toward the base .end or the louverand thus increasing therelative concentration of particles at that end. If nothing more were'done, this 'concentration'would ultimately increase to the criticalvalue at which the cloud would begin to lose particles through thelouver at a rate approximating the rate at which it receives particlesfrom the incoming air.

In accordance withmy invention, however, means are provided to removethe particles from the baseendof the louver. Accordingly inlet piece 9is spaced axially from disekplate 5 of the blower housing to provide anannular dust discharge opening Ill leading radially'outward from theinlet chamber at a point corresponding to theibase end portion of-theseparator which is at one side of the flow of primary air through theinlet chamber. Preferably an annular. sheet I l is arranged to extendaround dust discharge opening and between-the blower'housing and theinlet piece, to both of which it is connected, to form an: annularchamber or dust-ring l2 communicating through the dust opening I I],with the inlet chamber. .The' rotation of the louver will induce the airin dust ring [2 to rotate and the air forces causing that'induced flowalso cause particles of dust adjacent the base end of the louver to passoutwardly into the-[dust chamber. 7 I V In Figs 1-2, the dust-ring isprovided with outlet and inlet passages. l 3 and it through which it maybe connected to a hopper, not shown. With this arrangement the air inthe dust ring not only rotates through the dust ring but a portion bf"that air passes through outlet passage l3 into the'dust hopper'where thevelocity of the air is reduced so that some of the particles settle outof the air, the relative cleaner air flowing back into the dust ringthrough inlet passage I l. With induced circulation of this character,none of the primary air is diverted into the dust removal system.

The outward passage of the dust particles into the dust ring may befacilitated by providing the base end of the louver separator with aseries of blades I5 projecting radially from the separator through dustopening Hl into dust ring I2. Such blades will also effect a positivecirculation of air in the dust ring and hopper.

The Figs. 1-2 arrangement of dust opening l0, dust ring I2, and blades[5 is shown on an enlarged scale in Fig. 6. Referring first however to 6Fig. 5 which shows a similarly enlarged detail, it will be :noted thatthe axia1 dimensions of dust opening loa and dustring l2a areb'arelysufficient to accommodate the blades I5. With this Fig. 5arrangement, I have secured 94% eiiiciency ofseparationof particles in acertain size range. In Fig.' -6, however, the corresponding axialdimensions of dust opening Ill and dust ring l2 are greatly increasedso'that dust opening l0 overlies not only the base end of the separatorbutalso a substantial part ofthe base end portion of the vanes. Withthis arrangement, blades 15 cause the' air' in the dust'ring tocirculate axially or sidewiseas itrotates about the axis Of rotationand, in circulating axially, the dust ring air approachingthe bladesmingles with that portion of the mainair flow approaching the base endportion of the vanes. As a result, a better flow of cloud particles intothe dust ring is obtained without'the diversion of any primary air flow.With the Fig. 6 arrangement,I obtain a 67% increase in efficiency overthe efiiciency obtained withthe Fig. 5 arrangement, bringing the totalefiici'ency'to 98% with allother factors remain ingthes'ame. r

Fig. 7' shows an arrangement which'is substan: tially the sameas'thatshown in-Figs. 1-2'and 6, except thata part ofthe primary air isdiverted to the dust removingsystem for the purpose of creating apositive flow of air for sweeping particles from the base end portionofthe separator into the dust removal system. In this case,'dust ring [2is connected-by an outlet passage IE to a hopper ll where the air givesup at least part of its dust load, thetrelatively'clean air passingthrough conduit l8back into the inlet of the separator where it againmingles with the in coming air.':...

ii"Figs: 8* and 9 show an arrangement which is substantially the sameasthat shown in Figs. 1 2?and6, except that the inlet piece of theearlier figures is replaced here by a scroll'type of inlethousingwhichconstrains '.'the entering' 'air tofldw tangentially'so as to create arotating stream of air which moves axially over-the louver...Accordinglyia, scroll housing l9'is provided'having'f'a tangentiallydirectedinlet 20 and an axially directedioutlet "2| tof iriustro conicalshape. The conical shapex'of outletil'hasbeen foundito increase theseparating "efliciency somewhat; This arrangement operates insubstantiallyjthe same'way as the arrangements of the earlier'figures.The rotating body of air is made to :rotate preferably :in' thedirectionopposite to the direction" of. rotationof the louver,aalthoughit:.will be. understood that louver'rotation is not essential .in'this.case. The manner of particle separation'and removal'is the same asbefore. ..,..In Figs; 10 and .1'1, alouverconstructed in accordance-withm invention-is embodied in a housing. of'the cyclone type. This housinis conventionally fzprovided with; a; tangential inlet 22 leading into acyclone chamber having a conical bottom 23 and an axial outlet 24 todischarge clean air from the top of the housing. Louver separator L isplaced over the axial inlet of the discharge passage. It will be wellappreciated that the entering air rotates about the axis of the cyclonehousing and as it rotates, it moves axially toward and over the louverseparator L to pass through that separator and out of discharge passage24. Louver separator L functions in the same manner as previouslydescribed to form a cloud of particles around its upstream face. Theaxial component of the incoming air 7 operates to move dust particlestoward apex I of the louver separator and as the particles are thusmoved axially, they gradually settle out of the primary air flow intothe bottom of the conical hopper.

The arrangement shown in Fig. 12 is identical to that of Figs. 10-11,except that louver separator L is mounted for rotation within thecyclone housing. To this end discharge passage 24a of the cyclonehousing is secured to the axial inlet 2a of a blower impeller Ia.rotationally mounted within blower housing 311 and arranged to berotated by motor 25. When motor 25 is energized, the impeller will berotated to draw a stream of air through the cyclone discharge passage2611 into blower housing 3a. The separation of dust particles and theiraxial movement to the bottom of conical hopper 23 is effected in thesame way as described in connection with Figs. 10-11.

Fig. 13 illustrates a modification wherein the air being cleaned passesfrom the interior of a separator L to the exterior thereof asdistinguished from the reverse in Fig. 1. Separator L is preferably ofgenerally cylindrical shape with vanes 8a of much the same general shapeand size as those of Fig. 1 in the'side walls of the cylinder, thevanes'however being designed to intercept the dust particles on theinterior of the separator. The separator may be mounted on a shaft 4afor rotation. The clean air passes between vanes 8a into a surroundingscroll-type housing 26 having a discharge opening 21 connected tosuitable air suction means.

The intercepted dust continues travel in an axial direction along theinside of the separator until it passes into a dust ring 52?; which mayalso be of the scroll-type having a discharge opening at 28. The rightend of the assembly is closed by a wall 29, which prevents the escape ofdust particles except through the dust ring. Preferably impeller vanes|5a are secured to the right end of the separator to rotate therewithand aid in the removal of dust. Dust ring 12b may be formed as the dustring of Fig. 5 or the dust ring of Fig. 6.

In operation, the dirty air enters the interior of the separator at theleft end, the clean air passing out through the separator to housing 26and the dust to housing 28.

It will be noted that in all the embodiments shown herein, the dustparticles are moved to one side of the air flow, i. e., to the outsidein Fig. 1 and to the inside in Fig. 13, the particles being relativelyconcentrated adjacent one end of the louver, and that the means toremove the particles from the vanes is on that same side of the air flowso that it is not necessary for the concentration to enter or passthrough any portion of the main air flow before being removed. The dustparticles can be said to be gradually concentrated and edged out of theprimary air flow to a point where they are taken over by the 8 removalmeans' such' as the secondary air flow in the dust ring.

Having described my invention, I claim:

1. A louver dust separator for cleaning a main flow of air upon theestablishment of relative rotation between the incoming air and thelouver, comprising: a louver separator having a series of slot-defining,spaced blade-like vanes extending around an axis of rotation, with eachvane lying transversely across the path of the main air flow, and beinginclined in relation to the upstream face of the louver to'form an acuteangle which points in a direction opposite to the direction of rotationof the vane relatively to the approaching air, said vanes beingconstructed and arranged to prevent the passage of dust throughsaid'slots and thereby cause a cloud of dust particles to form on theupstream side of the vanes; means for constraining the incoming air flowto approach the louver in an axial direction such as to effect an axialmovement of cloud particles toward one side of the air flow and therebrelatively concentrate said particles adjacent one end of the louver; adust ring arranged on the same side of the air fiow to extend aroundsaid one end of the louver, said ring being outwardly spaced therefromand having an annular opening communicating with the space therebetween;and a series of blades mounted on the louver to project radially intosaid annular opening to induce the passage of dust particles throughsaid opening into the ring.

2. The louver separator of claim 1 wherein the axial dimension of thedust ring annular opening is substantially larger than the correspondingdimension of the blades at the point where they enter the opening, asubstantial portion of the opening being radially lined with the vanearea of the louver adjacent said one end.

3. The louver separator of claim 1 wherein the axial dimension of thedust ring is substantially larger than the corresponding dimension ofthe blades and the dust ring annular opening, and the blades arearranged to cause particles entering the dust ring to move axiallytoward one side of the ring.

STIG GZsON SYLVAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number 0 Name Date 992,260 Rush May 16, 19111,420,665 Newcombe June 2'7, 1922 2,039,127 Sylvan Apr. 28, 19362,209,607 Nutting July 30, 1940 FOREIGN PATENTS Number Country Date365,003 France June 15, 1906

